Pros and Cons of IVC systems

Pros and Cons of IVC
systems
By: Thomas C. Krohn
The Royal Veterinary and Agricultural
University
Copenhagen

The idea with the IVC

Different kind of ventilation

Why using IVCs
• Improved protection of the animals against
bacteria and vira
• Improved protection of the surroundings
against allergens or infections
• Improved micro climate in the cages
• Prolonged periods between cage changing

Protection against infections
• It is possible to protect the animals inside
the cage by running at positive pressure
• It is possible to protect at rack level as the
air is HEPA filtered, compared to
conventional systems where the protection
is at room level

Protection against allergens
• By using IVCs the reduction in the spread
of allergens from the cages is significant
• On positive pressure the reduction will be
at a factor 10
• On negative pressure the reduction is
more than a factor 100

Improved micro climate
• There is no build up of CO 2
• The humidity and temperature are kept as
the same level as the inlet air

Prolonged cage changing intervals
Ammonia (ppm)
350
300
250
200
150
100
50
0
Perkins & Lipman 1996
Static cage
Ventilated cage
1 2 3 4 5 6 7 8 9 10 11 12
Day

Problems with using IVCs
• Health monitoring problems
• Cage changing problems
• Requires constant ventilation

Health monitoring
• It is difficult to have a sentinel system
• Every cage is working as one closed unit

Cage changing
• The cage changing process is more time
consuming
• The cage changing has to take place in
special cage changing units

CO2-concentration (%)
10
9
8
7
6
5
4
3
2
1
0
Constant ventilation
0 20 40 60 80 100
Krohn et al., 2002
Static Filtertop IVC-system Totally sealed cage
Time (min)

General considerations
• Keep the number of air changes low (no
higher than 50 times per hour)
• Avoid systems with direct air send into the
cage at animal level
• Be careful when using the tight sealed
systems